Michigan State Police Lt. Mike Shaw, left, and Livingston County Sheriff Robert Bezotte listen to a speaker while standing next to a mugshot of Raulie Wayne Casteel. / Elizabeth Conley, AP

by Gina Damron and Tammy Stables Battaglia, Detroit Free Press

by Gina Damron and Tammy Stables Battaglia, Detroit Free Press

HOWELL, Mich. -- Raulie Wayne Casteel stood mostly silent and answered questions matter-of-factly as he was charged Wednesday with shooting at a moving vehicle on I-96.

Casteel was arraigned in Howell's 53rd District Court in just one shooting case, but authorities say he is suspected in 23 others, terrorizing motorists across four counties -- Oakland, Livingston, Shiawassee and Ingham -- for weeks.

As details emerge about how Casteel, 43, became a suspect, troubling new information also is coming out about the man whom a former neighbor called a "real nice guy," but whose mother worried is mentally ill.

Casteel was arraigned on one charge each of assault with a dangerous weapon, carrying a weapon with unlawful intent and intentionally firing a firearm from a vehicle and three counts of possession of a firearm during the commission of a felony in the Oct. 18 shooting. Casteel could be charged in other counties and federally, officials said.

The bulk of the shootings occurred Oct. 16-18. Only a handful occurred on I-96; the rest were along other roadways. Police have said the shooter was firing at drivers as they traveled in the opposite direction.

The only victim hit by gunfire was driving on I-96 in Livingston County. Three victims' vehicles were hit as they were driving along I-96.

Douglas Mullkoff, one of the lawyers hired to represent Casteel, said he hadn't met with his client before the arraignment. When the issue of bond arose, Mullkoff said Casteel has no criminal history and has strong family support.

A Twitter account that appears to belong to Casteel reveals a man engrossed in politics.

Some days, he would post dozens of comments. Posts called for President Obama to be impeached, called Michigan Gov. Rick Snyder a "traitor to the state" and complained about a sheriff's department in Kentucky, where he once lived, not taking seriously a complaint he had about military helicopters flying over his home.

A post dated Sept. 28 says, "The 2nd Amend is an absolute -- absolutely no compromises -- I carry everywhere I go!"

Records show Casteel once lived in Taylorsville, Ky., where he was president of Greek Oak Consulting, an environmental consulting and sustainable design firm.

Casteel's mother, Lana Hunt, told the Detroit Free Press she tried to get her son help, but could not get him to see a doctor. She said her son lives in Wixom, Mich., with his wife, a preschool-age daughter and other relatives.

A former neighbor in Brighton, where Casteel lived with his wife a few years ago, was shocked at the allegations.

"He was always willing to help out," Jack Taylor said of Casteel. "I would have never expected that of him. Something must have definitely went wrong."

Oakland County Chief Assistant Prosecutor Paul Walton said prosecutors in other counties could review charges on additional shootings as soon as this week.

More information about Casteel's arrest also emerged Wednesday.

Task force investigators re-interviewed victims over the weekend, and one witness remembered key details about the black, four-door car spotted during the crimes: A state-issued Michigan State University license plate with a green S on the left, surrounded by an MSU alumni license plate frame, according to State Police investigators.

A law enforcement source familiar with the investigation said investigators were able to track Casteel down through the Secretary of State once the details were narrowed down.

During a raid on his home Monday, police seized Casteel's car, which matches the description of the black four-door vehicle believed to have been used in the shootings. Michigan Secretary of State records show a 2009 Chevy Malibu registered in Casteel's name.

The task force said at least eight bullet fragments have been tied to the same handgun. Livingston County Prosecutor David Morse said police found a 9mm pistol in the search of Casteel's home.

Morse said Casteel had a license out of Kentucky to carry a gun, but was not licensed in Michigan.

Investigators said they received about 2,800 tips in the search for the shooter. Federal officials and Crime Stoppers were offering a $102,000 reward for information.